void SetCurrentLibrary(int n);
HWEXT_LIBRARY_MULTIPLE
extension bit has been set. See Extension plugins for details. In that case,
Hollywood will call SetCurrentLibrary()
to tell your plugin whose library's commands,
constants or base table you should return when Hollywood makes the next call to
your GetBaseTable(), GetCommands() or
GetConstants() functions. The library numbers passed by
Hollywood are 0-based, so a value of 0 means the first library. Hollywood will
call this function as many times as you've specified in your GetLibraryCount()
implementation. See GetLibraryCount for details.